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Hi guys. i have a 2003 x5 3.0L with 104k miles. My SES light came on with the code P0125: "Insufficient Coolant Temperature For Closed Loop Fuel Control. Engine temperature has not increased and/or reached the correct level within a specified amount of time after engine startup." I notice the engine tempature then shoot up on my dash board, waring the engine might overheat.

I live up in the mountains and it gets pretty cold here. First time my light came on i started my car up early in the moring and it was about 5F outside. I reset the light. I was good for a few days, then i started my car up tonight when it was super cold again drove a few blocks and had the same issue.

What should i check first to fix this thing? Over the past few months i've cleaned my MAF, replaced my DISA, pre cat-O2 sensors, and spark plugs... so no problems there. I hope this wont cost too much. Thanks for the insight!

I checked my coolant level today, it was low, i had to pour about a cup of water in there just to tide me over until i get my parts, at which time the coolant will be changed. Stange too, i noticed that stick that pops out of the expansion tank that measures the coolant level snaped in half somehow. So looks like i'll replace the expansion tank too, along with the water pump and thermostat. Anything else i need to change while im in there? Hoses still look good.

I checked my coolant level today, it was low, i had to pour about a cup of water in there just to tide me over until i get my parts, at which time the coolant will be changed. Stange too, i noticed that stick that pops out of the expansion tank that measures the coolant level snaped in half somehow. So looks like i'll replace the expansion tank too, along with the water pump and thermostat. Anything else i need to change while im in there? Hoses still look good.

Depending on how long it's been, I would change the temp sensor on the lower radiator hose. There's a little green oring that the sensor is sealed by which I would replace too.
That's a very common leak area. There is also a transmission thermostat on the bottom right hand side of the radiator, check for leaks there.
Good luck.

I would at 104K if it wasn't done recently. It can get brittle and beak off, or it could sieze and not allow proper cooling for the transmission. I changed mine at 140,000 on the V8 which is a little different, but I think it's why i was having rough shifting issues after a certain temp.

Got it... im shopping for parts now at bavarian autosports. Ever heard anything about JL Germany parts? They have a water pump thats only $27 with a metal impeller, thats like half the price.

If i wanted to just change the thermostat first, do i need to drain out all the coolant?

I ask because the NAPA autoparts down the street has a thermostat on the shelf for me I was hoping to just swap out real fast to temporarily fix the overheating problem. All the other stuff I had to order online to get a decent price, which means I will have to wait a week for free shipping or dish out like $60 for second day air. I'd hate to have to drain the coolant and bleed the system twice. I drive 20 miles a day to work and back and ground shipping takes a week.

Yeah, looks like i have to remove some coolant to replace that thermostat, so i guess i answered my own question.

Would you change the radiator as well?

And do you think i'll be good driving my car about 20 miles a day to work for the next week as long as i make sure the coolant level is good before driving? I'll pull the thing over as soon as the temp gauge goes into the red and wait for it too cool.